The field of electrosurgery includes a number of loosely related surgical techniques which have in common the application of electrical energy to modify the structure or integrity of patient tissue. Electrosurgical procedures usually operate through the application of very high frequency currents to cut or ablate tissue structures, where the operation can be monopolar or bipolar. Monopolar techniques rely on a separate electrode for the return of current that is placed away from the surgical site on the body of the patient, and where the surgical device defines only a single electrode pole that provides the surgical effect. Bipolar devices comprise two or more electrodes on the same support for the application of current between their surfaces.
Electrosurgical procedures and techniques are particularly advantageous because they generally reduce patient bleeding and trauma associated with cutting operations. Additionally, electrosurgical ablation procedures, where tissue surfaces and volume may be reshaped, cannot be duplicated through other treatment modalities.
Radiofrequency (RF) energy is used in a wide range of surgical procedures because it provides efficient tissue resection and coagulation and relatively easy access to the target tissues through a portal or cannula. Conventional monopolar high frequency electrosurgical devices typically operate by creating a voltage difference between the active electrode and the target tissue, causing an electrical arc to form across the physical gap between the electrode and tissue. At the point of contact of the electric arcs with tissue, rapid tissue heating occurs due to high current density between the electrode and tissue. This high current density causes cellular fluids to rapidly vaporize into steam, thereby producing a “cutting effect” along the pathway of localized tissue heating. Thus, the tissue is parted along the pathway of evaporated cellular fluid, inducing undesirable collateral tissue damage in regions surrounding the target tissue site. This collateral tissue damage often causes indiscriminate destruction of tissue, resulting in the loss of the proper function of the tissue. In addition, the device does not remove any tissue directly, but rather depends on destroying a zone of tissue and allowing the body to eventually remove the destroyed tissue.
Present electrosurgical devices used for tissue ablation in narrow anatomies may suffer from concerns associated with the difficulties that the device size may present in accessing certain treatment areas. Specifically, instances may arise where the device may have a shaft diameter that is too wide or shaft working length that is not sufficiently long making the desired access problematic. In additional, present devices used for tissue removal may suffer from poor visibility at the working end of the device where the overall size or orientation of the device tip obscures the physician's view of the surgical field. The inability to easily access and visualize the surgical field is a significant disadvantage in using electrosurgical techniques for tissue ablation, particularly in arthroscopic, otolaryngological, and spinal procedures.
Alternative devices for tissue treatment in narrow anatomies, such as CO2 lasers or microdebriders, may suffer from additional shortcomings in addition to obstacles attributed to the size of the device. For example, a CO2 laser may require a substantially longer set up time prior to the actual procedure, and such lasers are further impaired by relatively smaller tissue removal rate and increased collateral damage to tissue. Microdebriders typically are not afforded adequate hemostatis capabilities, resulting in the presence of significant amounts of blood likely contributing to blocked visibility of the surgical field and prolonged procedure times as other materials are required to stop bleeding.
Accordingly, improved systems and methods are still desired for precise tissue removal in narrow anatomies via electrosurgical ablation of tissue. In particular, improved systems operable designed to provide access to narrow anatomies while allowing increased surgical field visualization would provide a competitive advantage.